<?php

/* SVN FILE: $Id$ */
/**
 * SassMixinDefinitionNode class file.
 * @author      Chris Yates <chris.l.yates@gmail.com>
 * @copyright   Copyright (c) 2010 PBM Web Development
 * @license      http://phamlp.googlecode.com/files/license.txt
 * @package      PHamlP
 * @subpackage  Sass.tree
 */

/**
 * SassMixinDefinitionNode class.
 * Represents a Mixin definition.
 * @package      PHamlP
 * @subpackage  Sass.tree
 */
class SassMixinDefinitionNode extends SassNode
{

    const NODE_IDENTIFIER = '=';
    const MATCH = '/^(=|@mixin\s+)([-\w]+)\s*(?:\((.*?)\))?\s*$/im';
    const IDENTIFIER = 1;
    const NAME = 2;
    const ARGUMENTS = 3;

    /**
     * @var string name of the mixin
     */
    private $name;

    /**
     * @var array arguments for the mixin as name=>value pairs were value is the
     * default value or null for required arguments
     */
    private $args = array();

    /**
     * SassMixinDefinitionNode constructor.
     * @param object source token
     * @return SassMixinDefinitionNode
     */
    public function __construct($token)
    {
        preg_match(self::MATCH, $token->source, $matches);
        parent::__construct($token);
        if (empty($matches)) {
            throw new SassMixinDefinitionNodeException('Invalid Mixin', $this);
        }
        $this->name = $matches[self::NAME];
        if (isset($matches[self::ARGUMENTS])) {
            $this->args = SassScriptFunction::extractArgs($matches[self::ARGUMENTS], true, new SassContext);
        }
    }

    /**
     * Parse this node.
     * Add this mixin to  the current context.
     * @param SassContext the context in which this node is parsed
     * @return array the parsed node - an empty array
     */
    public function parse($context)
    {
        $context->addMixin($this->name, $this);
        return array();
    }

    /**
     * Returns the arguments with default values for this mixin
     * @return array the arguments with default values for this mixin
     */
    public function getArgs()
    {
        return $this->args;
    }

    /**
     * Returns a value indicating if the token represents this type of node.
     * @param object token
     * @return boolean true if the token represents this type of node, false if not
     */
    public static function isa($token)
    {
        return $token->source[0] === self::NODE_IDENTIFIER;
    }

}
